I just got my replacement today and the accelerometer worked at first, but a few hours later it got stuck at the exact same x-coordinate. I performed factory resets on both my first device and the replacement device to no avail. This is most definitely a hardware problem. Someone else who posted on an Android forum suggested that excessive heat from fast charging breaks the accelerometer chip:
"I'm on my 3rd S6 edge. It appears that they work out of the box but if you do a fast charge (making the battery very hot), the accelerometer chip seems to break. It might be the placement of the chip in relation to the battery, or it's possible that the chip maker just had a bad batch. Not sure if Samsung is using Invensense chips or not but I'm sure this is going to be something more than a little problem for Samsung and the chip maker if the numbers grow. It's possible this is only on the edge, which would lower the problems for Samsung."
Now that I think about it, my replacement device's accelerometer stopped working after I started charging it with the fast charger. If anyone else receives a new device, try avoiding the fast charger and see if this solves the problem. I will be going back to the Verizon store for a 3rd device and will test out this theory myself. If my 3rd device still breaks, I'm going to reluctantly go for the regular S6 which doesn't seem to have this problem.
